Is lack of sleep a potential factor in rising rates of obesity?

I noticed this news story yesterday, which reports on research published recently in the journal Obesity. The research, from Sweden, assessed the effects of sleep deprivation on food purchasing [1]. Fourteen men were given about $50 to spend on food in two settings: once after the men had a full night’s sleep, and once after a night of complete sleep deprivation.

In each setting, men were given a set breakfast in the morning to negate the effect of hunger on food purchasing decisions. During the shopping exercise, the men had had access to 40 items selected by the researchers. Half of these were ‘high calorie’ (> 2 calories per gram) and half of which were ‘low calorie’ (< 2 calories per gram). The study subjects were asked to purchase as much food as they could with the money they had available.

The results showed that after the night without sleep, the men purchased food that was more calorific (9 per cent more).

The researchers also measured levels of the appetite-stimulating hormone ghrelin in the morning. This was higher in the morning, overall, after the night without sleep. However, ghrelin levels did not correlate with purchasing decisions, so the higher levels of hormones is unlikely to explain the effect of sleep deprivation on the purchasing decisions.

This study is of some interest, I think, but is just part of a considerable and expanding body of evidence which suggests that sleep can influence body weight and composition. Sleep deprivation has been found to induce, among other things:

An increase in levels of inflammation in the body [2]. Inflammation in the body may participate in the poor functioning of hormones such as insulin (insulin resistance) and leptin (leptin resistance) – both of which are implicated in obesity. In one study, just one night of about 4 hours sleep was enough to impair insulin functioning [3].

Raised levels of the hormone ghrelin [4], as was observed in the latest study.

Increased hunger. In one study, stopping men sleeping for a single night led to them eating significantly more the following day [6].

Increased levels of the stress hormone cortisol [7] (excess cortisol can cause fat deposition, usually around the midriff).

Reduced metabolism of fat. In one study, disrupting men’s sleep with an alarm clock and allowing them only an average 6½ hours sleep, compared to no alarm clock and 8 hours sleep, caused their metabolism of fat of to fall by two-thirds [8].

Changes in body composition. In one study on the impact of sleep on weight loss, shorted sleep was found to reduce fat loss but increase muscle loss [9]. This effect may have something to do with the ability of sleep deprivation to increase levels of cortisol, as this hormone predisposes to fat gain and muscle loss.

Perhaps not surprisingly, some researchers have suggested changing sleep patterns over recent decades might be an important but under-recognised factor in the burgeoning rates of obesity and chronic disease [10]. I’m inclined to agree with this, and believe that going chronically short on sleep is a potential hazard that many of us can do something about.

I’ve found it can help a lot of people to reconsider their habitual bedtime, and just shift this forward a bit. This does not have to be every day and does not preclude people from having occasional late nights. It maybe means that if someone feels they do run short on sleep (and many people I work with do), they might consider going to bed maybe an or so hour earlier than they usually do.

One mental trick that can help here is not to view sleep as ‘unproductive time’, but as a core lifestyle habit that is important for both restoration of energy and general health and wellbeing. That way, sleep looks less like a ‘waste of time’ and more like something worthwhile properly investing in.

12 Responses to Is lack of sleep a potential factor in rising rates of obesity?

Have you heard of the 1st and 2nd sleep? Apparently it was quite common pre-electricity and presumably the 9-5 working pattern to split the sleep pattern into two intervals. This happens to me quite regularly and I now “go with the flow”.

John. I agree with your conclusions here but absolutely not with your implication that sleep shortage is a lifestyle choice…ie go to bed earlier etc.

Nearly everyone who is sleep short is probably looking at a set of other reasons, I know I am..insomnia and other disorders is not a lifestyle choice but I agree with the effects of being sleep deprived as regards obesity as you describe.

Imagine sleep deprivation does drive obesity through, for example, the mechanisms details above. At some point, an individual may end up not just overweight, but also perhaps unhealthy. Let’s say as a result of sleep apnoea they require more sleep. So, now our epidemiological data finds those who sleep for long periods are generally bigger, and shorter sleep is associated with ‘improved’ body weight.

This is why I try wherever possible to avoid basing advice on epidemiological evidence – it can be hopelessly misleading. And it’s why I didn’t mention epidemiological evidence it at all in the blog post, and all the evidence I cited is based on clinical studies.

I agree that a good night’s sleep is one of the best things you can do to improve your health. Lack of sleep not only contributes to obesity and other health problems, but the type of food you eat likely contributes to the quality of your sleep.

There is emerging evidence that over time a diet high in processed foods may adversely affect brain function, leading to a form of food-induced brain dysfunction called Carbohydrate Associated Reversible Brain syndrome or CARB syndrome. This process can eventually result in the depletion of monoamine neurotransmitters like dopamine and serotonin. Because the sleep hormone melatonin comes from serotonin, low serotonin means low melatonin and low melatonin means poor sleep.

They say: “you are what you eat”. I guess we could also say: “you sleep how you eat”.

I definitely agree with this article. I have sleep apnoea (OSA) together with restless leg syndrome (RLS) and periodic limb movement disorder (PLMD – 68 episodes an hour) all these conditions disturb my sleep and I am constantly tired. I attend the Sleep Clinic at St Thomas’ Hospital London and my treatment is a CPAP air pressure machine. However, all I keep getting told is to lose weight. I also have bruxism (teeth clenching and grinding) and when I saw the dentist at Guys Hospital for a teeth guard as I was smashing all my teeth – he told me it was the anatomy of my neck which caused the apnoea etc.. I would love to lose weight and its only lately that I’ve realised that the low fat diet is not the way to do it but to increase my protein foods. I’m introducing these foods slowly and getting off the grains/carbs but after a lifetime of eating all the wrong foods (since the 1980′s) – I guess it will be a slow journey.
Many thanks for this information as it keeps me focused and motivated.

Not just sleep more but sleep better? Anyone over about 40 can readily compare the world pre and post constantly being ‘wired’ /on line. We used to say ‘turn on , tune in’(!)-maybe now it should be ‘turn off, tune in’-for your good physical and mental health…keep the nights dark and the spirit calm!

I found that I loose weight when I am on holiday and sleep long hours.
However, if I sleep the same amount when at work, only go to bed earlier, I don’t feel rested and there is no similar effect. My sleep seems to be disturbed.

Not sure why that is:

1. Perhaps my body clock prefers me to stay awake later at night. Maybe for me sleeping 1am to 9am provides a better rest than 11pm to 7am.
Perhaps we all have some optimum sleeping patters that do not coincide with others.

2. Perhaps my sleep is disturbed because I don’t like my job. No an easy remedy there

“I found that I loose weight when I am on holiday and sleep long hours.
However, if I sleep the same amount when at work, only go to bed earlier, I don’t feel rested and there is no similar effect. My sleep seems to be disturbed.”

What kind of holiday do you take, and where? What do you do when on holiday, and aside from the obvious what is different about being at home (and the routine of work) as opposed to being away on holiday? Do you spend time swimming in the ocean, for instance, can you discern you get more of something when on holiday (or less), or more exposure to something or other (or less)? There is a possible explanation, there could be several, and I have one in mind, but I have no wish to prompt you.

At various times I have worked long hours, odd hours, and irregular hours that are not entirely within my control. When I leave the door for work I have little prior knowledge nor say in my return. Setting routines is tricky, and at times this has added significatly to the levels of fatigue I sometimes tolerate.

It seems to me to be so obvious, and it has been for so for several years, that fatigue, that accumulated fatigue that catches up on you after a succession of sleep cut short, is my greatest trigger for over-eating. That said, for many years this very clear ‘fact’ totally escaped my notice.

Recently I switched to the backshift (1400-2230) and for the first time in years I established a routine, knew percisely what time I would be home, settled soon after, slept all I needed, and woke refreshed. Without any special effort on my part I lost 10 kilos in as many weeks, and the result came as surprise. Lamentably I exited that job, and went back to early starts with irregular finishing times, and I have gained a bit of weight since.

Fatigue leads to a lack of engagement with the task in hand, reduced concentration and application, and far greater urges to snack along the way (in the least it does with me). Worse, fatigue has me craving carbohydrate foods which I know can disrupt hormonal balance and can greatly encourage the laying down of body-fats. Even knowing this to be the case is of little help against the compulsive aspects of it.

I think it is too easy for people, for workers, and for employers, to overlook the significance that sleeping times and measures of sleep may have upon general well-being and long term prospects of health.

I think much more research needs to be done in this area. A lack of sleep may contribute to weight gain but I don’t think it is the whole story. Other emotional factors can equally create problems such as stress or anxiety for starters. Sadly there is never a magic answer that solves the problem but a complex tangle of issues and problems.

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